This project focuses on long-term consequences of individual differences in physical, social, and affective functioning and the description of early interaction in diverse ecological contexts. Extensive observations of infant-mother interaction and attachment in multiple samples revealed that, regardless of social or ethnic background, mothers spent comparable amounts of time in discrete activities such as feeding, caring for, and playing with their infants. Systematic analyses demonstrated that the quality of social interaction within dyads changed dramatically depending on the functional and social context. As a result, extended observations were necessary to obtain reliable indices of individual differences. Comparable day-long observations of parents and infants in Quebec, Germany, the Central African Republic, and Colombia, as well as in African-American families in the US, are being conducted to further explore the effects of culture and context on early interactions. At least two samples are being drawn from each culture sampled to maximize insight into the sources and interpretation of variability. We hope that systematic and detailed observations of parents and infants in a variety of ecological contexts will provide a clearer understanding of the content to which infant experiences vary and of the best ways of obtaining reliable indices of individual differences within and between cultures.